Low-pressure alarm



N0M0de1.) i

F. 1... STREET. LOW PRESSURE ALARM.

N0. 511,818. Patented Jam. 2, 1894. 1

vthe triple valves UNTTsn STnTEs FRANCIS LEONARD STREET,

HALF TO EDIVIN L.

LOW-PRES SPECIFICATION forming pari of Application led July 22,

PATENT @Trina OF NEODESHA, KANSAS, .ASSIGNOR OF ONE- FAY, OF SPRINGFIELD, MISSOURI.

SURE ALARM.

Letters Patent N o. 511,818, dated January 2, 1894.

1891. Serial No. 400,300. (No model.)

To @ZZ 10A/tom zit may concern:

Be it known FRANCIS LEONARD STREET, a citizen of the ing at Neodesha, 1n the county of Tilson and State of Kansas, have nd useful Improvements in Low-Pressure pressure railto those operated by air. For the sake of simplicity, my Invention as applied lto the well-known Vestinghouse system, though it is adapted for use with other systems.

n essential feature of the W'estinghouse automatic brake system is the maintenance in the train pipes ofapredetermined air pressure. The train pipe is in connection through With the auxiliary reservoirs I shall describe under th either accidentally or intentionally, the triple valves operate to admit the air from the reservolrs into the brake cylinders and apply the brakes; but if the reduction of pressure feed valve in the engineers valve gets stuck, or if the pump fails to operate properly, the supply of air to the train pipe ceases, and the reduction in pressure due to leakage may become so great as to render the brakes useless. It is customary to connect a pressure gage with the train pipe in the cab of the locomotive, so that the engineer can ascertain at any time the condition of his aim but it frequently happens that the necessity of Watching the track, looking out for signals, and other imperative duties, so engross his attention that the engineer sometimes forgets to look at his air gage.

The object of my invention is to give an audi le Warning when the pressure in the train pipe reaches a dangerously low point.

To this end my invention consists in providing a suitable outlet from the train pipe, having' a valve which is held normally closed by the air pressure, but which opens auto e falls below The air may exert its pressure either directly upon the valve, or upon a piston or diaphragm attached thereto.

In the drawings Figure l is a longitudinal Section of my alarm, and a portion of the engineers valve. Fig. 2 is a bottom plan View of the valve proper. Fig. 3 is a diagrammatic plan of the valve and alarm.

The engineers Valve proper, A, is made as usual, with the addition of a small radial recess a out in the outer wall of the cavity a. Then the handle is in the running position, as shown in Fig. 3, this recess registers With a small hole b drilled down into i cavity a laps over the direct application supply port, as shown in Fig. 3, and said port is always in communication With the train pipe. The hole b is tapped to receive the threaded end of the Valve casing C, or a pipe leading thereto.

ner end of the casing, its stem e, which is preferably squared, grooved or ribbed, projecting into the central chamber, in which a helical spring F is located, compressed between t-he end of said stem and the screw D.

IOC

tud e', fixed in thel stem e, plays in a slot the valve remains open, substantially as de- 55 the casing to limitv themovernent of the scribed.

Ve. The screw D is tubular, and attached 2. A low pressure alarm for automatic air its head d is a whistle G of any suitable brake systems, consisting of a valve controltstruction. The one shown consists of tWo ling an outlet from the train pipe, a sprmg leave disks united at their edges, each havarranged to open said valve when the air 6o :a central perforation. pressure falls to a given point in the train lhe operation of my device is as follows: pipe, and a whistle adapted to be sounded by .e spring F is adjusted to force the valveE the escaping air, said outlet communicating en against the air pressure in the holesb continuously with the entire train pipe so when said pressure falls below, say, forty long as the valve remains open, substantially 65 'e pounds. The air then iiows out through as described.

e casing and tubular screw to the whistle, 3. The combination with an engineers ving an audible alarm, which continues valve having the cavity c and a passage itil the engineer again establishes the norleading from said cavity to the atmosphere, al pressure in the train pipe. Should he when the engineers valve is in the running 7o eglect to do this, the air will escape rapidly position of a valve controlling said passage, ioughI through the alarm to soon set the a Whistle communicating with said passage rakes gently, and eventually stop the train. and a spring adapted to open the valve and he device is thus an efficient safeguard even permit the air to escape when the train pipe the whistle fails to sound. pressure falls below a predetermined point, 75 The alarm may be located at the point X or substantially as described.

.rinstead of at the place shown: in fact, it 4. The combination with an engineers nay be placed anywhere in connection with valve having the cavity ct and a recess a, at

he train or small reservoir pipes. When arone side thereof, and provided with a passage anged as illustrated in the drawings, the leading to theatmosphere and adapted to reg- 8o vhistle will cease to sound the instant the ister with the recesso, when the valve handle iandle H is moved awa 1 from the running is in the running position, of a valve controlposition, since the recess a will thereby be thrown out of coincidence with the hole b.

ling said passage, a whistle communicating with said passage and a spring adapted to When the alarm is at the point X orY it will continue to sound until the pressure in the open said valve when the train pipe pressure 85 falls below a given point, substantiallyas detrain pipe is restored to the normal.

My alarm is simple in construction, and

scribed.

costs but little. It can be easily applied to` 5. A low pressure alarm for automatic air brake systems, consisting of the casing C, the

the engineers valve, and does not interfere valve E seating against the end ofthe casing, 9o

with the proper operation of said valve. the tubular screw D, an audible alarm com- The details of construction may be considmunicating with said tubular screw and the erably varied without departing from the spring F, arranged between the valve stem spirit of my invention. The necessity for such a device, and the success of my inven- 'and the screw and adapted to force the valve away from its seat, substantially as described. 95 tion in meeting the need, have been fully demonstrated by me in practice.

6. The combination with the casing C of the valve E seating against the end of the casing Having thus described my invention, what and having a stem e, the tubular screw D, the

. I claim, and desire to secure by Letters Patspring F between the screw and the valve ent,is stem, and the whistle G attached to the outer loc 1. A low pressure alarm for automatic air end of the screw substantially as described. brake systems, consisting of a valve control- Intestimony whereof l affix my signature in lilng an outlet from the train pipe, an audible presenceot two witnesses.

a a arm communicating with said outlet, and a T 1 1 1^ y spring for opening said valve when the train FRAB CIS LEONARD S1 REET pipe pressure falls below a predetermined Witnesses: point, said outlet communicating continu- JOHN LYDON,

ously with the entire train pipe as long as G. L. HOYT. 

